Fluid mixing and spraying apparatus

ABSTRACT

A fluid mixing and spraying apparatus and method. The apparatus includes a body having an elongated chamber with a diffuser positioned therein having a central passageway with an entrance end and an exit end. The diffuser has an end wall at the exit end of the central passageway. The end wall of the diffuser has a plurality of spaced openings to permit a first fluid supplied to the entrance end of the passageway under pressure to exit through the openings into the elongated chamber as a plurality of streams. An intermediate portion of the diffuser has a peripheral recessed portion which defines a distributing chamber for receiving a second fluid under pressure. A plurality of channels formed in the diffuser extend from the recessed portion to the end wall to permit the second fluid in the distributing chamber to exit from the chamber through the channels into the elongated chamber as a plurality of streams to mix with the first fluid. Baffle means also may be provided in the elongated chamber beyond the point where the two fluids first meet and mix to further facilitate mixing of the two fluids prior to their discharge through a fluid spray tip.

United States Patent 1 Fram et al.

[111 3,759,450 [451 Sept. 18,1973

[ FLUID MIXING AND SPRAYING APPARATUS [75] Inventors: Morris Fram, Dunland; Robert D.

Hetherington, Sunland; Craig Freeman, Van Nuys, all of Calif.

[73] Assignee: Ransburg EIectro-Coating Corp.,

Indianapolis, Ind.

[22] Filed: Mar. 16, 1972 [21] Appl. No.: 235,356

[52] US. Cl 239/427, 239/430, 239/432 [51] Int. Cl B05b 7/04 [58] Field of Search 239/398, 437, 434.5,

[56] References Cited UNITED STATES PATENTS 1,331,376 2/1920 Quinn 239/427 2,489,031 3/1947 I-Iillringhouse. 239/398 X 2,933,259 3/1958 Raskin.... 239/419 X 2,930,532 3/1960 Johnson 239/398 X Primary Examiner-Allen N. Knowles Assistant Examiner-Andres Kashnikow Attorney-Merrill N. Johnson et al.

[ ABSTRACT A fluid mixing and spraying apparatus and method. The apparatus includes a body having an elongated chamber with a diffuser positioned therein having a central passageway with an entrance end and an exit end. The diffuser has an end wall at the exit end of the central passageway. The end wall of the diffuser has a plurality of spaced openings to permit a first fluid supplied to the entrance end of the passageway under pressure to exit through the openings into the elongated chamber as a plurality of streams. An intermediate portion of the diffuser has a peripheral recessed portion which defines a distributing chamber for receiving a second fluid under pressure. A plurality of channels formed in the diffuser extend from the recessed portion to the end wall to permit the second fluid in the distributing chamber to exit from the chamber through the channels into the elongated chamber as a plurality of streams to mix with the first fluid. Baffle means also may be provided in the elongated chamber beyond the point where the two fluids first meet and mix to further facilitate mixing of the two fluids prior to their discharge through a fluid spray tip.

4 Claims, 4 Drawing Figures Second Fluid First Fluid BACKGROUND OF THE lNVENTlON 1. Field of the Invention This invention relates generally to a fluid dispensing apparatus and method, and, more particularly, to a fluid mixing and spraying apparatus and method wherein the apparatus employs a perforated and slotted diffuser to facilitate the mixing of at least two different fluids.

2. Description of the Prior Art Various apparatus are known for dispensing or spraying a plurality of fluids. One apparatus, described in U.S. Pat. No. 3,330,484 issued .luly ll, 1967, internally mixes fluids to be sprayed immediately prior to ejecting the mixture of fluids through a suitable fluid spray tip or nozzle. Another apparatus, described in US. Pat. No. 3,399,834 issued Sept. 3, 1968, mixes the fluids by spraying individually each of the fluids and then commingling the sprayed fluids externally of the apparatus in such a manner as to efiect mixing. Each of the above-mentioned apparatus has been'used for mixing and spraying fluids such as plastics of the polyester resin type. Polyester resins are often used to provide a coating wherein the plastic is formed by suitably mixing a catalyzing agent such as methyl ethyl ketone peroxide or the like with a resinous material such as polyester resin or the like. Moreover, in manufacturing fiberglas reinforced plastic products, certain operations also require the formation and sprayingof a mixture of resinous plastic materials and catalyzing agent. The resin and catalyst can be mixed in a spray apparatus and then sprayed onto a mold or part, or mixed externally of spraying apparatus and then sprayed onto a mold or part. In the operation of the apparatus, it is important that the catalyst be satisfactorily mixed into the resin or undesirable results can occur such as uneven hardening of the resin. It is also desirable to keep at a minimum, the amount of air utilized by the device to provide the spray since the use of large quantities of air during operation of the device tends to create an undesirable amount of fumes.

Several known mixing and spraying apparatus have not satisfactorily mixed the resin and the catalyst materials, while other known mixing and spraying apparatus have utilized large quantities of air to mix and atomize the fluids into a suitable spray.

SUMMARY OF THE INVENTION Among the features of the present invention is to avoid the disadvantages of prior artmixing and spraying apparatus enumerated above. Another feature of the present invention is to provide a fluid mixing and spraying apparatus which facilitates mixing of at least two fluids such as a polyester resin and a catalyst. Still another feature of the invention is to provide a diffuser which accommodates a plurality of fluid flows of a first fluid such as a polyester resin, and accommodates a plurality of fluid flows of a second fluid such as a catalyst/air mixture and causes each of the plurality of flows of the first fluid and of the second fluid to be satisfactorily mixed. A further object of the invention is to provide a fluid mixing and spraying apparatus which includes a diffuser which divides a first fluid such as polyester resin into a plurality of fluid streams which pass from the diffuser at an angle to the longitudinal axis of a chamber in which the diffuser is located, and which i type are particularly adapted to spray a variety of ther- 2 divides the second fluid such as air/catalyst mixture into a plurality of fluid streams which pass from the diffuser substantially parallel to the axis of the chamber, and then mixing the divided fluid streams adjacent the diffuser. Still another feature of the invention is to provide a fluid mixing and spraying apparatus which is simple in construction.

in the presently preferred embodiment of the fluid mixing and spraying apparatus, the apparatus includes a body having a spray head, an elongated chamber, and a diffuser positioned in the chamber. The diffuser is provided with a central passageway having an entrance end and an exit end. A first fluid passageway in the body communicates with the entrance end of the central passageway to provide a first fluid under pressure for passage therethrough. The exit end of the central passageway is covered by an end wall having a plurality of spaced openings therein to permit the first fluid to exit through the openings as a plurality of streams into the elongated chamber. The end wall openings are positioned at an angle to the longitudinal axis of the elongated chamber so that the first fluid exits towards the periphery of the chamber.

The diffuser is provided with a peripheral recessed portion generally intermediate of its length which dehires a distributing chamber which in turn has a second fluid passageway communicating therewith to provide a second fluid under pressure to the distributing chamher. A plurality of channels in the diffuser extend from the recessed portion to the end wall to permit the second fluid in the distributing chamber to exit therefrom through the channels into the elongated chamber as a plurality of streams to mix with the first fluid whereupon the mixture of the two fluids may be ejected or discharged through a suitable fluid spray tip. Baffle means comprised of a plurality of spaced discs each having a cutout portion therein to permit the mixture of fluids to pass therethrough may be positioned between the diffuser and the fluid spray tip to further facilitate mixing of the two fluids prior to spraying.

BRIEF DESClON OF THE DRAWINGS Other features and advantages of the invention will become apparent by reference to the more detailed description of the invention and the accompanying drawings which follow herein:

FIG. 1 is a side elevational view of a spray head of a spray gun having a mixing and spraying apparatus according to the present invention mounted therein;

FIG. 2 is a sectional view taken along line 2-2 of FIG. 1 showing details of the mixing and spraying apparatus according to the present invention;

FIG. 3 is an end view taken along line 3-3 of FIG. 3; and

FIG. 4 is a sectional view taken along line 4-4 of FlG. 2.

IDESCRIJPTlON OF THE INVENTION the front portion of the body of a spray apparatus such as spray gun 10 having a spray head 11 attached thereto with a threaded front portion 12 for receiving an internally threaded collar 13 thereon. The spray apparatus or gun W may be of any suitable type, such as that shown anddescribed in Johnson et al., US. Pat. No. 3,330,484 issued July 11, 1967. Spray guns of this mosetting plastics, catalyzed glues, gel coats, liquid foams, etc.

Referring now to FIG. 2 for a more detailed description of the concepts of the invention, the body of spray head 11 is provided with a central elongated chamber 20 having a smaller end portion 21 and an enlarged intermediate portion 22, a continuing threaded portion 23, a further enlarged intermediate portion 24 and an enlarged outer end portion 25. A nozzle body member 26 is threadably attached at its inner end to the threaded portion 23 of the chamber 20.

The nozzle body member 26 has a threaded inner end portion 27 followed by a recessed portion 28, an enlarged intermediate portion 29 and a further enlarged intermediate portion 30 from where the body then decreases in size in a plurality of steps until it reaches its end 31. The nozzle body member 26 further is provided with an elongated cylindrical central chamber 32 extending therethrough. Chamber 32 forms a continuation of the central cylindrical chamber 20 of the body of the spray head 11.

Recessed portion 28 of nozzle body member 26 forms a circular distributing chamber 35 with the intermediate portion 24 of the body of the spray head 11. The chamber 35 communicates with the elongated central cylindrical chamber 32 of the nozzle body member 26 by means of a plurality of spaced apertures or holes 36 as shown in FIG. 4. As illustrated, the recessed portion 28 may contain four such apertures or holes 36, each spaced about 90 degrees apart. It is to be understood that any number of a plurality of apertures 36 can be provided as long as the desired results are achieved.

The body of the spray head 11 is provided with a first fluid passageway 40 which is supplied with a first fluid under pressure from a suitable conduit 41 suitably connected thereto and extending from the main body (not shown in FIG. 2) of the spray gun 10. If the mixing and spraying device of the present invention is to be used to spray a thermosetting plastic material, the conduit 41 is preferably used to supply a resin material under a suitable pressure to the first fluid passageway 40. A suitable resin material is a polyester resin.

The body of the spray head 11 is provided with a second fluid passageway 42 which is supplied by a second fluid under pressure from a suitable conduit 43 suitably connected thereto and extending from the main body (not shown in FIG. 2) of the spray gun 10. This second fluid may be a mixture of air under pressure and a catalyst. A suitable catalyst is methyl ethyl ketone peroxide. The fluid passageway 42 terminates at its inner end at the'circular distributing chamber 35 formed by the recessed portion 28 of the nozzle body member 26.

A diffuser 50 is positioned at the inner end of the elongated cylindrical central chamber 32 of the nozzle body member 26 and partially in the enlarged intermediate portion 22 of the chamber 20 of the body of the spray head 11. The diffuser 50 is comprised of a cylindrical body portion 51 having an enlarged ring 52 at its inner end which is received by the enlarged intermediate portion 22 of the chamber 20. A suitable sealing means such as O-ring 53 is positioned around the inner end of diffuser 50 between the ring 52 and the end of enlarged intermediate portion 22 of the chamber 20.

The diffuser 50 is provided with a central passageway 55 extending therethrough from its inner end to its outer end. The passageway 55 is covered at its outer end by end wall 56 which preferably is in the configuration of a conically shaped tip as shown in FIG. 2. The end wall 56 is provided with a plurality of spaced openings or perforations 57 which are formed in the end wall so as to be positioned substantially perpendicular to the angled face of the conical tip. It should be seen that the openings 57 are also positioned at an angle to the longitudinal axis of the elongated cylindrical central chamber 32 of the nozzle body member 26 so that fluid passing through the central passageway 55 exits through the openings 57 towards the periphery of the chamber 32 as a plurality of streams of fluid.

The diffuser 50 is also provided with an annular intermediate recessed portion 58 on its periphery to form an annular distributing chamber 59 for receiving fluid under pressure from the second fluid passageway 42 through circular distributing chamber 35 and the apertures 36.

The portion of the diffuser 50 between the annular intermediate recessed portion 58 and end wall 56 is provided with a plurality of parallel spaced channels or grooves 61 as shown in FIG. 4. Preferably, each of the channels 61 is aligned with one of the end wall openings 57. It will be appreciated that a fluid supplied under pressure to the annular distributing chamber 59 will be divided into a plurality of fluid streams by the channels 61 and will pass from the channels 61 to the elongated cylindrical central chamber 32 ahead of or beyond the end wall 56 of the diffuser 50.

It will be appreciated that the channels 61 divide the second fluid such as an air/catalyst mixture into a plurality of streams while the end wall openings 57 divide the first fluid such as a resin into a plurality of streams. Preferably, the number of streams of air/catalyst mixture is equal to the number of resin streams. Since the streams of the first fluid exit through the openings 57 of the end wall 56 at an angle directed outwardly towards the periphery of the elongated cylindrical central chamber 32, the streams of the first fluid will readily mix with the plurality of streams of the second fluid which is discharged through the channels 61 adjacent the periphery of the chamber 32 and substantially parallel to the longitudinal axis of the chamber 32. In this manner a substantial mixing of the two fluids occurs.

A baffle means 63 may be positioned in the elongatedcylindrical central chamber 32 spaced beyond or ahead of the end wall 56 of the diffuser 50. The baffle means 63 is comprised of a central rod 64 having a plurality of spaced discs 65 projecting therefrom. In the embodiment shown in FIG. 2, the baffle means 63 includes three spaced discs 65. Each of the discs 65 is provided with a plurality of cutout portions 66. The cutout portions 66 of each of the discs 65 may be aligned to form a plurality of channels to provide a tortuous path for the mixture of the fluids which serves to tumble and whip the mixture of fluids for further mixing.

A suitable fluid spray tip 70 is aligned with the end of chamber 32 of nozzle member 26 and is retained in position by annular flange 60 at the front end of the threaded collar 13. The fluid spray tip 70 is provided with a central passageway 71 for receiving the mixture of fluids exiting from the baffle means 63. As shown in FIGS. 2 and 3, the fluid spray tip 70 is provided at its outer end with a substantially V-shaped notch 72. The central passage 71 in the fluid spray tip 70 terminates at notch 72 in a sharp edged elliptical orifice 73 through which the mixture of fluids is ejected. The mixture of fluids upon being ejected from the orifice 73 is caused to be atomized by the interaction of the mixture with the atmosphere surrounding the spray tip 70. The spray of the atomized mixture of fluids is caused to spread out in a fan-like shape by virtue of the notch 72 and the elliptical shape of the orifice 73 of the spray tip 70 for application to the desired surface.

A suitable sealing means such as O-ring 75 is positioned between the inner end of the fluid spray tip 70 and the end of the nozzle member 26. Other suitable sealing means such as O-rings 76 and 77 are provided on the intermediate portions 29 and 30 of the noule member 26 to form a seal between the nozzle body member 26 and the spray head 11.

In operation of the mixing and spraying apparatus of the present invention, a first fluid under pressure such as a polyester resin is provided to the spray head lll through conduit 41 to first fluid passageway 40 into the central elongated chamber 2d through the central passageway 55 of the diffuser 50. The polyester resin exits through the special openings 57 in end wall 56 as a plurality of separate streams at an angle directed outwardly towards the periphery of the chamber 32. It should be noted that the streams of polyester resin pass from the diffuser 50 at an angle to the longitudinal axis of the chamber in which the diffuser is located. A second fluid under pressure such as an air/catalyst mixture is supplied to the spray head ll through the conduit 43 to the second fluid passageway 42 and into the circular distributing chamber 35 through the openings 36 into the second distributing chamber 59 from where it exits through the channels 61 as a plurality of separate streams into the chamber 32 of the nozzle body member 26. It should be noted that the streams of air/ catalyst mixture pass from the diffuser 50 substantially parallel to the longitudinal axis of the chamber in which the diffuser is located. The streams of the air/catalyst mixture exiting from the channels 61 meet the streams of resin exiting from the openings 57 at a point in front of the end wall 57 so that mixing of the two fluids is facilitated.

After the two streams are substantially merged into one mixture, the entire mixture then flows through the tortuous path provided by the spaced discs 65 of the baffle means 63 where the mixture is further tumbled and mixed. The mixture then is ejected from the elliptical orifice 73 of fluid spray tip 70 under pressure where it interacts with the surrounding air in such a manner as to be atomized.

The advantages of the present invention are believed readily apparent from the above description. The dif- 5 fuser member provides an efficient and simple means for initially maintaining two fluids separate until mixed just prior to being ejected or discharged from the spray tip 70. The baffle means 63 provides further mixing of the two fluids just prior to ejection from the spray tip 70. Bythis arrangement, if an air/catalyst mixture is employed as one fluid, the air acts as both a carrier for the catalyst and may be used to assist in breaking up the flow of the two fluids into a spray. Moreover, the spraying and mixing can be accomplished with a minimum amount of air.

The mixture ejected from the spray gun 10 can be atomized by subjecting the mixture to high pressure prior to ejection, by using air to atomize the mixture or by using other suitable mechanical means to atomize the mixture. 6

It should be appreciated that the concepts of the present invention are applicable to spraying of most plural component materials including, but not limited to, polyester resins, epoxy resins, urethane resins, silicone rubber and the like. Generally, the plural component material is converted, at ambient atmospheric temperature, from a liquid phase to a solid phase by the addition of an appropriate catalyst or curing agent. Polyester resins may be cured by the addition of a peroxide catalyst and a naphthenate or aniline promoter. Epoxies may be cured by the addition of a suitable amine or anhydride curing agent thereto. Urethanes may be obtained by the addition of a suitable isocyanate ester to a polyester resin. Silicone rubber may be obtained by the addition of a suitable tin soap to a silicone elastomer.

Although the present invention has been illustrated and described with reference to a specific embodiment, it will be understood that various modifications may be made by persons skilled in the art without departing from the spirit of the invention which is defined solely by the appended.

We claim:

l. A fluid mixing and spraying apparatus comprising a body having a chamber,

diffuser means positioned in the chamber and having a passageway with an entrance end and an exit end,

a first fluid passageway in the means communicating with the entrance end of the passageway to provide a first fluid under pressure for passage therethrough,

an end wall of the passageway having a plurality of spaced openings therein to permit the first fluid to exit therefrom as a plurality of streams into the chamber,

a portion on the diffuser defining a distributing chamber,'

a second fluid passageway in the means communicating with the distributing chamber to provide a second fluid under pressure thereto,

a plurality of channels in the diffuser extending from the distributing chamber to the chamber and to permit the second fluid in the distributing chamber to exit therefrom through the channels into the chamber as a plurality of streams and mix with the first fluid, and

baffle means positioned between said end wall and said fluid spray tip to further mix said fluids prior 7 to spraying.

2. Afluid mixing and spraying apparatus as defined in claim 1, wherein the end wall is in the form of a conical tip at the exit end of the passageway and the openings are formed perpendicular to the face of the tip so that the first fluid streams exit therefrom toward the periphery of the chamber. a

' 3. The fluid mixing device as defined in claim 1, wherein the plurality of channels in the difiuser are positioned so that the plurality of streams of the second fluid exit from the diffuser substantially parallel to the longitudinal axis of the chamber.

4. A fluid mixing device as defined in claim 3 wherein each of the openings from which the first fluid is projected is aligned with the means for dividing the second fluid into a plurality of streams.

a a: r 1: s i 

1. A fluid mixing and spraying apparatus comprising a body having a chamber, diffuser means positioned in the chamber and having a passageway with an entrance end and an exit end, a first fluid passageway in the means communicating with the entrance end of the passageway to provide a first fluid under pressure for passage therethrough, an end wall of the passageway having a plurality of spaced openings therein to permit the first fluid to exit therefrom as a plurality of streams into the chamber, a portion on the diffuser defining a distributing chamber, a second fluid passageway in the means communicating with the distributing chamber to provide a second fluid under pressure thereto, a plurality of channels in the diffuser extending from the distributing chamber to the chamber and to permit the second fluid in the distributing chamber to exit therefrom through the channels into the chamber as a plurality of streams and mix with the first fluid, and baffle means positioned between said end wall and said fluid spray tip to further mix said fluids prior to spraying.
 2. A fluid mixing and spraying apparatus as defined in claim 1, wherein the end wall is in the form of a conical tip at the exit end of the passageway and the openings are formed perpendicular to the face of the tip so that the first fluid streams exit therefrom toward the periphery of the chamber.
 3. The fluid mixing device as defined in claim 1, wherein the plurality of channels in the diffuser are positioned so that the plurality of streams of the second fluid exit from the diffuser substantially parallel to the longitudinal axis of the chamber.
 4. A fluid mixing device as defined in claim 3 wherein each of the openings from which the first fluid is projected is aligned with the means for dividing the second fluid into a plurality of streams. 